1. Field of the invention
The present invention relates to display technology, and more particularly, to an electro-static discharge protective circuit and a display substrate and a display device having the same.
2. Description of the Related Art
Electro-Static Discharge (ESD) protective circuit is an important part of a liquid crystal display device and of an organic luminescence display device. Such protective circuit is capable of protecting the display device from electrostatic damage during production, transportation and operation. FIG. 1 shows configuration of an electro-static discharge protective circuit in the prior art. This protective circuit comprises four thin film transistors M1, M2, M3 and M4. When the signal line S works normally to perform signal transmission, all the four thin film transistors M1, M2, M3 and M4 turn off so that the protective circuit does not perform a protection function. When there are positive electrical charges accumulated on the signal line S, the thin film transistors M1 and M2 turn on and the accumulated electrical charges are discharged from the signal line S to the high level end VGH, thereby achieving the electro-static discharge. When there are negative electrical charges accumulated on the signal line S, the thin film transistors M3 and M4 turn on and the accumulated electrical charges are discharged from the signal line S to the low level end VGL, thereby achieving the electro-static discharge.
The abovementioned ESD protective circuit is capable of protecting the display device from electrostatic damage in certain degrees, however, when there is a great amount of electrical charges accumulated on the signal line S, there is still a high risk that the circuit connected with the signal line S is breakdown and fails.